Move time to complete stats into separate class

This separates out the calculations from the queries so we can get
decent tests around them.

app/models/stats/actions.rb

@@ -8,23 +8,8 @@ module Stats
       @user = user
     end
 
-    def avg_ttc
-      @avg_ttc ||= (sum/count)/SECONDS_PER_DAY
-    end
-
-    def max_ttc
-      @max_ttc ||= max/SECONDS_PER_DAY
-    end
-
-    def min_ttc
-      @min_ttc ||= min/SECONDS_PER_DAY
-    end
-
-    def min_ttc_sec
-      min_ttc_sec = arbitrary_day + min # convert to a datetime
-      @actions_min_ttc_sec = (min_ttc_sec).strftime("%H:%M:%S")
-      @actions_min_ttc_sec = (min / SECONDS_PER_DAY).round.to_s + " days " + @actions_min_ttc_sec if min > SECONDS_PER_DAY
-      @actions_min_ttc_sec
+    def ttc
+      @ttc ||= TimeToComplete.new(completed)
     end
 
     def done_last30days
@@ -69,10 +54,6 @@ module Stats
 
     private
 
-    def arbitrary_day
-      @arbitrary_day ||= Time.utc(2000,1,1,0,0)
-    end
-
     def one_year
       @one_year ||= 12.months.ago.beginning_of_day
     end
@@ -81,32 +62,6 @@ module Stats
       @one_month ||= 1.month.ago.beginning_of_day
     end
 
-    def completed
-      @completed ||= user.todos.completed.select("completed_at, created_at")
-    end
-
-    def durations
-      @durations ||= completed.map do |r|
-        (r.completed_at - r.created_at)
-      end
-    end
-
-    def sum
-      @sum ||= durations.inject(0) {|sum, d| sum + d}
-    end
-
-    def min
-      @min ||= durations.min || 0
-    end
-
-    def max
-      @max ||= durations.max || 0
-    end
-
-    def count
-      completed.empty? ? 1 : completed.size
-    end
-
     def new_since(cutoff)
       user.todos.created_after(cutoff).count
     end
@@ -115,5 +70,8 @@ module Stats
       user.todos.completed.completed_after(cutoff).count
     end
 
+    def completed
+      @completed ||= user.todos.completed.select("completed_at, created_at")
+    end
   end
 end

app/models/stats/time_to_complete.rb

@@ -0,0 +1,59 @@
+module Stats
+  class TimeToComplete
+
+    SECONDS_PER_DAY = 86400;
+
+    attr_reader :actions
+    def initialize(actions)
+      @actions = actions
+    end
+
+    def avg
+      @avg ||= (sum / count) / SECONDS_PER_DAY
+    end
+
+    def max
+      @max ||= max_in_seconds / SECONDS_PER_DAY
+    end
+
+    def min
+      @min ||= min_in_seconds / SECONDS_PER_DAY
+    end
+
+    def min_sec
+      min_sec = arbitrary_day + min_in_seconds # convert to a datetime
+      @min_sec = min_sec.strftime("%H:%M:%S")
+      @min_sec = min.round.to_s + " days " + @min_sec if min >= 1
+      @min_sec
+    end
+
+    private
+
+    def min_in_seconds
+      @min_in_seconds ||= durations.min || 0
+    end
+
+    def max_in_seconds
+      @max_in_seconds ||= durations.max || 0
+    end
+
+    def count
+      actions.empty? ? 1 : actions.size
+    end
+
+    def durations
+      @durations ||= actions.map do |r|
+        (r.completed_at - r.created_at)
+      end
+    end
+
+    def sum
+      @sum ||= durations.inject(0) {|sum, d| sum + d}
+    end
+
+    def arbitrary_day
+      @arbitrary_day ||= Time.utc(2000, 1, 1, 0, 0)
+    end
+
+  end
+end

app/views/stats/_actions.html.erb

@@ -1,6 +1,6 @@
-<p><%= t('stats.actions_avg_completion_time', :count => (actions.avg_ttc*10).round/10.0) %>
-<%= t('stats.actions_min_max_completion_days', :max => (actions.max_ttc*10).round/10.0, :min => (actions.min_ttc*10).round/10.0) %>
-<%= t('stats.actions_min_completion_time', :time => actions.min_ttc_sec) %></p>
+<p><%= t('stats.actions_avg_completion_time', :count => (actions.ttc.avg*10).round/10.0) %>
+<%= t('stats.actions_min_max_completion_days', :max => (actions.ttc.max*10).round/10.0, :min => (actions.ttc.min*10).round/10.0) %>
+<%= t('stats.actions_min_completion_time', :time => actions.ttc.min_sec) %></p>
 
 <p><%= t('stats.actions_actions_avg_created_30days', :count => (actions.created_last30days*10.0/30.0).round/10.0 )%>
 <%= t('stats.actions_avg_completed_30days', :count => (actions.done_last30days*10.0/30.0).round/10.0 )%>

test/unit/time_to_complete_test.rb

@@ -0,0 +1,75 @@
+require 'date'
+require 'time'
+require './test/minimal_test_helper'
+require 'app/models/stats/time_to_complete'
+
+FakeTask = Struct.new(:created_at, :completed_at)
+
+class TimeToCompleteTest < Test::Unit::TestCase
+
+  def now
+    @now ||= Time.utc(2013, 1, 2, 3, 4, 5)
+  end
+
+  def day0
+    @day0 ||= Time.utc(2013, 1, 2, 0, 0, 0)
+  end
+
+  def day2
+    @day2 ||= Time.utc(2012, 12, 31, 0, 0, 0)
+  end
+
+  def day4
+    @day4 ||= Time.utc(2012, 12, 29, 0, 0, 0)
+  end
+
+  def day6
+    @day6 ||= Time.utc(2012, 12, 27, 0, 0, 0)
+  end
+
+  def fake_tasks
+    @fake_tasks ||= [
+      FakeTask.new(day2, now),
+      FakeTask.new(day4, now),
+      FakeTask.new(day6, now)
+    ]
+  end
+
+  def test_empty_minimum
+    assert_equal 0, Stats::TimeToComplete.new([]).min
+  end
+
+  def test_empty_maximum
+    assert_equal 0, Stats::TimeToComplete.new([]).max
+  end
+
+  def test_empty_avg
+    assert_equal 0, Stats::TimeToComplete.new([]).avg
+  end
+
+  def test_empty_min_sec
+    assert_equal '00:00:00', Stats::TimeToComplete.new([]).min_sec
+  end
+
+  def test_minimum
+    assert_equal 2.127835648148148, Stats::TimeToComplete.new(fake_tasks).min
+  end
+
+  def test_maximum
+    assert_equal 6.127835648148148, Stats::TimeToComplete.new(fake_tasks).max
+  end
+
+  def test_avg
+    assert_equal 4.127835648148148, Stats::TimeToComplete.new(fake_tasks).avg
+  end
+
+  def test_min_sec
+    assert_equal '2 days 03:04:05', Stats::TimeToComplete.new(fake_tasks).min_sec
+  end
+
+  def test_min_sec_with_less_than_a_day
+    task = FakeTask.new(day0, now)
+    assert_equal '03:04:05', Stats::TimeToComplete.new([task]).min_sec
+  end
+end
+